[Please note, regarding the commentary on the text "Philosophumena" and its author, which was as yet unknown to the Church in the 19th century: By early 20th century, it was recognized that the author of the Philosophumena was none other than St. Hippolytus of Rome, who for a time set himself against St. Callixtus as an antipope, yet was later reconciled to the Church, suffered martyrdom for the Faith alongside Pope St. Pontian, and has been honored as a saint since the earliest centuries. This understanding had not yet been established in Dom Guéranger's time.]Pope Saint Callixtus I, who reigned from about 217 to 222, was a former slave who rose through hardship to become one of the early and most influential popes of the third century. Having been condemned to forced labor in the mines of Sardinia for his Christian faith, he was later freed and placed under the protection of Pope Zephyrinus, who entrusted him with the administration of the Church’s cemetery along the Appian Way—now known as the Catacombs of Saint Callixtus. As pope, Callixtus faced intense opposition from rigorists like Hippolytus for his merciful policies toward repentant sinners and his defense of the Church’s unity against schism. He emphasized forgiveness and inclusivity, affirming that the Church could reconcile even grave sinners after penance. Martyred during a local uprising under Emperor Alexander Severus, he was buried in the cemetery of Calepodius on the Aurelian Way, and his feast is celebrated on October 14.Dom Prosper Guéranger's The Liturgical Year, a monumental fifteen-volume work, offers a comprehensive exploration of the Catholic Church’s liturgical calendar, guiding readers through the spiritual and historical richness of the Church’s worship. Written in the 19th century, the series provides daily meditations, historical context, and liturgical texts for the Mass and Divine Office, covering the entire cycle of seasons—Advent, Christmas, Lent, Passiontide, Easter, and the Time after Pentecost—as well as feast days of saints. Guéranger’s work, rooted in a deep contemplative spirit, aims to immerse the faithful in the Church’s prayerful life, emphasizing the unity of faith through the axiom lex orandi, lex credendi ("the law of prayer is the law of belief"), and remains a cherished resource for Catholics seeking to deepen their spiritual lives. Dom Prosper Guéranger (1805–1875) was a French Benedictine monk, liturgical scholar, and founder of the Solesmes Abbey, renowned for his pivotal role in reviving the Benedictine Order in France and restoring the Roman liturgy after the disruptions of the French Revolution. Born in Sablé-sur-Sarthe, he entered the priesthood in 1827 and, inspired by a vision to restore monastic life, reestablished the Benedictine community at Solesmes in 1833, becoming its first abbot. A staunch defender of ultramontanism and traditional Catholic worship, he also championed the revival of Gregorian chant, significantly influencing the liturgical renewal movement.Link to the Dom Guéranger's Liturgical Year playlist (updated daily, unless a ferial day): https://www.youtube.com/playlist?list=PLZKdyYnV_bkh7rH6piW0ShgsdcefFoOvJ